The Port River Dolphins usually have calves every 3-4 years. Calves are normally born tail first and the mother helps to nudge the calf to the surface so it can take its first breath. The calves suckle milk from their mothers and may nurse for up to 18 months. They usually start learning to catch small fish when they are only about 6 months old.
Calves can take a few months to learn to swim properly and will often lift their whole head out of the water each time they take a breath. They spend a lot more time on the surface and are not as quick as the older dolphins; it is therefore extremely important that people using watercrafts keep an eye out and do not approach them.
Mothers and calves form very strong bonds; the calves usually stay very close to their mothers and will swim along in the “slip stream” the mother creates as she glides through the water. The mortality rate for baby dolphins in the Port River is very high, unfortunately around 50% of the baby dolphins do not survive their first year. There are many threats that the Port River Dolphins face including pollution, being hit by boats or caught in fishing line.
Like humans dolphins also grieve if they lose their baby. Often if they lose their calf they will push the body around, sometimes for several days. It is a heartbreaking sight to see and even more heartbreaking to think that us humans may be responsible for some of these deaths.
The surviving calves do not generally leave their mothers until they are about 3-4 years old. They will often head off on their own a few months before the mother has another calf.
When calves are still young they are very dependent on their mums and it is not until they are old enough to do so (usually at least 2 years of age) that they may venture away. Sadly one of our calves Ali, lost her beautiful mum, Millie (possibly due to a boat strike) when Ali was only eight months old. At this age Ali should still have been relying on her mum for milk and therefore her chances of survival were very slim. Incredibly Ali survived all odds, she is well over a year old now and appears healthy and has been seen at times by herself but also spending time with some of the other dolphins. Hopefully she will continue to do well and will continue to grow and learn from the other dolphins within the Port River Pod.
While calves are with their mothers they learn about social interactions and feeding techniques. They will watch their mother’s behaviour and the behaviour of other dolphins within the pod and will often try to imitate them. They learn an incredible amount in the first few years of their lives.